應用限制理論於晶圓廠良率管理之實證研究

Abstract

良率的高低是晶圓廠相當重要的一個績效指標，它代表著晶圓廠生產的產品品質，是客戶滿意的重要因素，也會直接影響到與客戶的合作關係。由於晶圓廠每天所重視的指標是產出量與生產量，相關單位為了獲得良好的績效當然是全力配合生產單位的需求，竭盡所能致力於保持機台的使用率，使機台的產出量最大為原則，所以各個單位就想盡辦法不使機台停機，努力的要維持機台的效能，看起來是要保護產出，但實際上卻是極力的重視部門（局部）績效，反而傷害了組織整體績效。

目前遇到的問題是產品品質出了問題時，在歸屬責任上，無法讓每各部門樂意接受，因此延誤了整個解問題的速度造成更大的損失。本研究期望能製訂一些方法及原則，以利在發現異常，分析問題，追查真因及解決問題時能夠很流暢的、和諧的運作。使每個部門都能主動地去追查問題及解決問題，使每個階段都有相關單位負責，不致使問題沒有人理會。本研究主要是從生產線上的缺陷檢查著手，探討整個運作過程中所發生的衝突，造成良率的影響。

本研究應用限制理論的思考程序，依據改變什麼？改變成什麼？如何改變？三大步驟，由不良效應分析出核心問題，建構現況圖，撥雲見日圖，未來狀況圖，必要條件圖，轉換圖，發現應該將重點專注在員工面對異常問題時的心態之改善，而發展出五個戰術目標：1.規劃基層主管的教育訓練；2.建立工程回饋系統及制度；3.以積極的態度面對問題；4.生產記錄包含所有的問題；5.制訂適當且明確的甄選準則，有助於改善現行的運作方式做好良率管理的工作。

For the wafer fabrication, the yield of wafer represents the quality of production processes is a very important and influence on the profit. In other words, the wafer fabrication’s qualities of product and customer’s satisfaction are increased with the increasing yields, which also affect the cooperation of customers. In terms of wafer outputs and production. Regulating authorities pursue the goal of good performance of preventing any prejudice and satisfying the product authorities’ demand. Regulating authorities also devote to keep the machines’ utility rate and maintain the machines’ efficiency. It seem to protect the throughput, In fact, it actuality maintain the department’s (partial) effects, instead, it injures the organization’s whole effects.

The lack of responsibility in solving the poor quality of product is the most important problem these days. Seldom departments recognize the duty to solve such problem. It belongs to duty, and unable to accept pleased at departments. However, this causes the delay in solving the problems and hence results in a huge loss. The main objective of this study is to provide methods and rules to investigate unusual events, analyze problems, find out the sources of the problem and finally solve problems. It makes in regulating authorities charge in every steps. Rather than handled by engineers. The study is major confering from defect inspection on production line, and then the conflicts bring about yield influences.

The study applies Theory of Constraint (TOC) thinking process, which includes three main steps (What to change? To what to change? How to cause the change? ) to analyze the core problem from UDEs, construct the Current Reality Tree (CRT), Evaporating cloud, Future Reality Tree (FRT), Pre-Requisite Tree (PRT) and Transition Tree (TT) to find out the point on the engineer who handles the problems. Finally, five tactics objectives are developed: 1. Program the basic level manager’s training; 2.Build the feedback system and rule with respect to engineering; 3.Solve the problems positively; 4. Production parers record all the problems; 5.Determine the proper and well-defined selection criteria. These objectives may improve operations of the company and reach better yield management.